Core for use in the molding of hollow articles



May 3, 1938. c. B. MATHEWS CORE FOR USE IN THE MOLDING OF HOLLOW ARTICLES Filed March 19, 1955 3 Sheets-Sheet l May 3, 1938. c. B. MATHEWS 2,116,464 CORE FOR us IN THE MOLDING OF HOLLOW ARTICLES I 3 Sheets-Sheet 2 Filed March 19, 1936 QMJ WAQ y 3, 1938. c. B. MATHEWS 2,116,464

GORE FOR USE IN THE MOLDING OF HOLLOW ARTICLES Filed March 19, 1936' 5 Sheets-Sheet 3 V/W////// //////////j I ovre/vrae CM 6W hid-Run 8r 1 M, M

nrrae/vzr Patented May 3, 193a I 2,116,464

VUNITED STATES PATENT OFFICE CORE FOR USE IN THE MOLDING OF HOL- LOW ARTICLES Charles Bernard Mathews, Lobs Wood, Middleton, Ilkley, England, assignor of one-half to John Goldwell Ambrose, Beaconsfield, England Application March 19, 1936, Serial No. 69,650 In Great Britain April 4. 1935 3 Claims. (Cl. 25-r128) This invention relates to the construction of in a, monolith formed in the usual manner and cores for use in the manufacture of hollow arshowing how I arrange for the tube to be inticles of concrete or the like, and consists in the flated by the application of gas or liquid under employment of flexible material for constructpressure.

ing an outer covering or bag for enclosing an Fig. 4 is a diagrammatical view of a fragindia-rubber tube which, when inflated, will ment, showing how the flexible material has to make-it assume the shape or contour of the debe formed to receive the inner inflating rubber sired space that it will leave when molded withtube to be expanded therein to produce the core in the article produced. As for example the as shownby Fig. 3.

core may be cylindrical in cross section or rec- Fig. 5 is a sectional end elevation on line A--B tangular or other shape in cross section, and the (Fig. 3) and as seen from left to right of said formation or construction of the flexible bag figure.

(which may be of woven cotton, or of canvas, Fig. 6 is a similar end elevation of a section or leather or like material) is such that when' of a member of concrete with the additionof a an elastic tube or tubes (as of indie-rubber) is shaped core produced as is hereinafter de- 15 or are placed within the flexible bag and inflated scribed. or distended, the shape or contour which said Figs. 7 and 8 are elevation and sectional plan expanding bodies assume will approximately fill showing the method followed in using my cores the whole of the interior of the flexible bag to to form the wall of a building.

2 produce the effect desired, and such inflation or Fig. 9 is a perspective plan showing a frag- 2o distension may be effected by air under pressure, ment of a floor and ceiling of a room with our steam under pressure, air orsteam combined cores inserted and the concrete placed thereon under pressure, or water or other liquid presas hereinafter described. sure may be employed. Fig. 10 is a. diagrammatical section showing The moldin of articles of concrete or like mahow the cover may be withdrawn from its poterial, as is well known, requires the hollow shape sition in a molded article. 25 or contour and number of cores to ill] the 1101- The formation of a core, according to my inlow spaces which they have subsequently to vavention, in one of its simplest forms is to make cate so that the outside of said molded article such core p rf tly y d a nasmu h as the will be of the desired shape, while the displaceinner tube 2 of india-ru'bber takes the form of a 30 merit of the core leaves it hollow for the sake cylinder when inflated and therefore the formaof lightness and for other purposes in using the tion of my core o the P p as ow by g. molded article as circumstances necessitate, such 1 y requires the est a ning tube 3 to be also as the making of pipeways in the ground for the of flexible, non-elastic material, which, in this 5 conveying of water or other liquid matter, gas case, is of woven or like fibrous substance such or the like, the making of monolithsinmclds, the as of cotton, flax, hemp or the like, and is made building of walls, floors and ceilings of buildings, to extend from the open end shown in Fig. 1 culverts or other formations, and further like the entire length and beyond the inner tube 2 of structures. india-rubber.

40 In order that my said invention may be more The formation of the tube 3 may be effected 40 easily understood I have hereunto appended by the process of weaving in well known mansheets of drawings which, by letters and figures, ner, or it may be of appropriate width so that reference is made in the following description:--- the two outer edges may be folded over and Fig. 1 is a perspective view which diagramstitched together to form the restricting size of matically shows how a pipe may be formed in the tube. This tube is of sufllcient diameter 45 the ground with metal reinforcing means which when inflated that it will restrict the full inflawill strengthen same circumferentially when tion of the elastic tube 2 to form the desired completed. diameter of hole or opening in the concrete struc- Fig. 2 is an endelevation showing an opening ture which is to be formed. made in a concrete block which is fortified with Taking over this tube 3 and extending in a 50 metal bars extending longitudinally through similar manner the entire length of the tube 3 same. is another tube 3a secured to it with a final cover Fig. 3 is a sectional plan of a core placed 5 of flexible material loosely placed over all the within a molding box, which core is intended to three (the tube 2 and two flexible tubes 3, 3a), form the opening or. hollow space to be left withand this cover (when the tubes within are infiated) will also be forced outwardly to assume the full size of the complete core.

In making use of the core thus produced and with a supply valve and coupling member b at one end thereof for the supplying and retaining of air or the like under pressure, I can then place at the base of the gutter a sufficient concrete to act as the base I of the final concrete member that has to be constructed within the gutter a, so that the core may be laid therein where, after the core has been expanded to the desired diameter, the remaining concrete may be filled into the gutter to cover or form the required enclosure of said core to complete the entire structure.

After filling in, and after the fixing or hardening of the concrete above the core, I deflate or release said core of its entire internal pressure,.thereby reducing its diameter and therefore rendering same free to be removed as desired.

This deflating of the core causes the inner casing of india-rubber 2 to bring with it the outer coverings 3 and 3a which enclose same, but does not bring with it the outermost covering 5 of the core, and same remains within the concrete structure to which it adheres.

After the whole removal of the core I then arrange a tape i2, hereinafter shown and described, having one end fixed to the end of the outermost core 5 so that I can then lay hold of the other end of this tape i2 and withdraw the inner cover 5 from its adhering position by causing its walls to roll inwardly from oil? the wall of concrete and the whole core may thus be withdrawn as is hereinafter more fully explained by reference to Fig. 10.

Provided the structure 4' of concrete has to be extended, before replacing the core 2 in position, I arrange the concrete structure 4 to continue along the gutter in the ground, of the shape forming the base of said concrete structure, as shown by Fig. 1. After this I place the end of the core slightly into the end of the previously cast structure of concrete and then, after indating the core I commence to fill the gutter in the ground to the desired depth of concrete as before stated, so that the whole structure is finished ready for the filling in of earth or covering the space in which the concrete lies, as circumstances require.

If the completed concrete structure encircling the core requires to be reinforced I can reinforce it circumferentially by the addition of a coiled strip of wire 6 which extends lengthwise the core and surrounds same, care being taken that the said coil of wire is embedded in the base, side walls and cover of the concrete structure as is shown by Fig. 1.

Provided the concrete structure, as shown at in in Fig. 2, requires further reinforcement I can make use of a series of cradles 1 into which take the longitudinal wires 8 so that said wires 8 may be laid within the concrete in a manner well known to extend the full length of same or any part thereon as may be required.

The other members 1a for supporting the wires I towards the upper part of the structure may be made use of and may, together with said wires 8, be left within the concrete structure.

when making a core to form an open space within a concrete structure as is shown by Figs. 3, 4 and 5 of the drawings I can make use again of the inner tube 2 of india-rubber which I fold upon itself to form three sections d, e and 1. Over the tube 2 -I place a cover 3 and this cover I I form by weaving or superposing two of the flexible fabrics upon each other and stitching or otherwise securing them along their outermost edges d and l and along the two edges e and e as far as the extent of the tube 2 reaches within the other portion e of the cover I.

The tube of India-rubber 2 is inserted into the portion d of the cover 3 by inserting a thin bar of metal through same along the part d. The cover 3 has its outer ends at d and e closed by stitching or otherwise, and the insertion of the tube 2 therein is effected by placing its outer end into the section d of the tube a and inserting a lacing bar through an opening made in the outer end d of said tube, its insertion being so far extended that the end of the tube 2 may be fixed to it. The metal bar is then withdrawn to bring the tube 2 beyond the end of the part e of the tube 3. The metal bar is then removed and is reinserted along the end of the cover 3 to be again attached to the tube 2. This is then drawn into the end portion of the cover 3 and the bar detached so that it may be inserted into the end of the part I of the cover 3 to withdraw the tube out of the open end of the part I. In like manner the tube 2 is bent over and the metal bar is inserted to pass again through the end part of the cover 3 to reach and draw within it the outermost closed end of the tube 2 to lie within the full length of the part e of the cover 3. The openings through the cover 3 for the insertion of the operating metal bar as stated are then repaired.

To complete the construction of the core I add a further outer covering flexible member 5 which is of the right dimensions to enable it to take over the whole outer surface of the covering 3. This outer covering 5 is for the purpose of facilitating its removal and the removal of all the parts it contains, as is hereinafter explained.

The inner cover 3 is formed to have the three parts d, e and J in the relative positions shown, in order to restrain the innermost tube 2 of indiarubber from assuming a cylindrical shape when inflated, but allowing it to assume the form somewhat as is indicated by Figs. 5 and 6, while the other covering tube of inextensible' but flexible material is permitted to be distended by the pressure of inflation to form the upper and lower faces fiat and even, while their edges are of semi-cylindrical shape.

It is obvious that where strength is required, or weight has to be resisted, then the flexible coverings 3, 3a may be increased in number or thickness, while where the increased thickness of concrete block requires a core of larger thickness or other difference in shape, then the central part e of the cover 3 and the other covers 3a and 5 have to be of larger width to allow the whole core to be distended to the shape somewhat as shown by Fig. 6. In the molding of the block of concrete or monolith within a box (as shown by Fig. 3) I arrange the ends of the core to take through a detachable stop piece 2i (preferably of wood) which has to be removed when taking the core from its position within the molded concrete.

When I desire to form a wall or structure (as shown by Figs. 7 and 8) I may use vertical planks or battens of timber l3 which are fixed in position on the ground to stand erect so that they may carry metal supports I4. Between these series of planks l5, mounted upon the battens or upright structures I3, I may suspend series of cores ii to be supported in position by a cross bar I'l so that they will extend between the wall formed or produced by concrete filling the space along each side of the cores l6, and around, as well as between, the spaces 3 (which will afford binding means for the structure) in order to form the wall continuous but in sections as desired, in 7 order that when the cores are deflated and withdrawn the structure is completed.

When it is desired to use additional binding means to retain the outer surfaces of the wall with the space .9 between them, I employ binding pieces 1. which I insert as shown by Fig. 8 so that they will extend from being embedded in the wall at one side to be embedded also in the wall opposite, and any desirable position may be selected for placing the series of these cross binding parts t, either vertically or laterally the appropriate distance apart.

When I make use of a series of cores 3 (shown by Fig. 9) for forming a floor 3| and a ceiling 32 I may arrange them in pairs or in larger numbers to extend between the floor and the ceiling as shown by said figure, and when so arranged I leave near the edge (where they have to be withdrawn from their positions) oval openings which are sufiicient to permit the deflated core to be withdrawn from them. In this case the cores 3 are of any shape formed most suitable, somewhat as ls shown by the drawings, so that the said openings 30, when made through the concrete forming the floor 3|, may be made narrow enough and yet broad enough to permit the withdrawal of said cores 3 through them after said cores have been deflated.

When the cores have been withdrawn and the concrete thoroughly set and hardened the openings leading to the-cavities vacated by the cores may be filled up to leave the floor in a finished condition.

As is hereinbefore stated I make use of a detachable cover throughout all the formations of concrete structures within which a core 3 is employed, so that I may withdraw said covering 5 from its position when all the other parts have been removed to liberate it to be so withdrawn by the employment of a tape or cord I! which may extend longitudinally through the structure as shown by Fig. 10.

Whenthecord llisbeingusedtowithdraw the cover 5 from its said position it carries another cord In inwardly which loosely drags behind so that when the core has been fully withdrawn by turning it from the outside to the inside the tape I2a will follow said turning action and will therefore remain on the inside of the cover 5. By these means it may be possible to replace the cover 5 on its core that has been withdrawn by acting upon it with the tape I241 and inserting it at the end where the tape l2 reaches, then by withdrawing the tape 12a the functions of said withdrawal cause the tape [2 to return and bring the core to the inside of the cover 5. The turning actions at the points and w of the cover 5 make the detachment of said cover from the adhesive actions of the concrete more easily executed. Such being the nature and object of my said invention, what I claim is:-

l. A core for molding hollow concrete articles, which comprises an elongated inflatable member, said member being bent so as to have a plurality of sections thereof disposed side by side, an inelastic flexible covering for each said section of said member, and an additional covering enveloping the entire bent member.

2. A core for molding hollow concrete articles, which comprises an elongated inflatable member, said member being bent so as to have a plurality of sections thereof disposed side by side, an inelastic flexible covering for each said section of said member, and an additional covering envelopcover being stitched together betweenthe parallel sections of the tube, and a second cover of flexible but inextensible material enveloping said tube and'inner cover.

CHARLES' BERNARD MA'I'HEWB. 

